50 posts from May 2014

May 31, 2014

Tomorrow kicks off my 2014 storm chasing trip from Denver, Colorado. Today I'm traveling to Denver from Louisville and keeping up with weather data as I go along. The reason our storm chasing group (Storm Chasing Adventure Tours) is based out of Denver this time of year is because the severe storm threat generally moves northward later in spring. Early spring storms tend to be in the Southern Plains, which is why earlier tours are based out of Oklahoma City.

Right on cue, the storm threat lately has shifted toward the Central and Northern Plains. Tonight a shortwave trough aloft will move from the West Coast into the Rocky Mountain region, generating some faster southwest winds at about 18,000 ft. As the sun rises over the High Plains tomorrow an area of low pressure will develop in Eastern Colorado in response to the trough aloft moving in over the mountains. The process by which this happens on the eastern side of the Rockies with upper-level lift and wind support is called lee-side cyclogenesis. As this is all happening a cold front will be moving in from the north, complicating the setup a bit.

Where we travel to tomorrow will likely be dictated by where the greatest wind shear sets up. Right now that looks like somewhere near the central part of the Kansas/Nebraska border given the easterly surface winds that both the NAM and GFS models have there with the tightening low pressure, but then in Southeastern Colorado. These easterly surface winds increase low-level shear, and thus the chance for rotating supercell thunderstorms and tornadoes. Should that low not tighten as much the easterly winds might be positioned a bit north. In any case, it looks like there will be enough moisture, instability, and a dry air push from the west (helps to generate lift) for storms to get going. Overall wind shear (the difference between surface winds and those aloft) is a little weak, so the tornado threat doesn't look all that big. It is there though since we do have the prerequisites for it in other categories. I'm also concerned that these supercell storms will blob together into a line of storms later on in the evening. How fast that happens will determine how long we'll be able to chase them since it's much more difficult to chase a line of storms as opposed to individual stronger supercells. Hopefully this process will wait until well past sunset when we'll be done chasing anyway. We'll evaluate the data in the morning and make a final decision then. The Storm Prediction Center (SPC) has issued an upper-end 30% Slight Risk due to the severe weather threat, which is an upgrade from yesterday's 15% risk that was issued.

It looks like Monday and Tuesday could be active chase days as well. The SPC has a 5% severe risk over parts of the Central Plains on Monday, which could get updated to a Slight Risk per their latest discussion. There's also a risk outlined in Nebraska/Kansas on Tuesday. Hopefully we'll have some good storms to chase!

Nice to see a break in the humidity today and it appears E/NE winds will keep us in check today in keeping the higher dewpoints to our southwest.

But notice how close the cutoff is to our southern counties. I still cannot rule an isolated storm in that area with such a setup. Louisville ...north/east looks good.

By the time we head into Sunday, things change. The cold front washes out..and that allows for the moisture to seep back into the region. Therefore we have to add a risk for an isolated thunderstorms.

The humidity really has a grip on us next week with the main front of action to our north. Still some debate how close that front will get to us during the weekend. Nevertheless, the atmosphere will be tropical in nature and will continue to be the focal point afternoon showers/storms.

Most of these look to be pulse-type storms. The upper level winds are not there to maintain the updrafts long enough for them to become widespread severe storms.

The only exception to that looks to be late Monday into early Tuesday. There looks to be a wave passing to our north that may have just enough shear for stronger storms. Highest chance across IN/OH. We will watch that.

Otherwise, just a week more like "July" expected.

I am still tracking the risk for something tropical the first weekend of June in the Gulf. GFS has hammered this idea hard for over a week...and now other models starting to join in. Location and timing still highly uncertain, but there is a risk for something orgnaized in this region near the 10th of June.

Interestingly enough, the latest GFS turns the tropical system towards us in a much weaker fashion a few days after. That would give quite the soaking rain for us. But ...just one model run. Who knows yet.

Hurricane Season in the Atlantic officially starts tomorrow. It will end November 30th.

May 30, 2014

Tomorrow I'll be heading to Denver, Colorado to embark on my seventh year of storm chasing out in the Great Plains. This is part of a yearly tradition that started in high school when Storm Chasing Adventure Tours founder Todd Thorn stumbled upon some of my weather-related online videos and contacted me to see if I would be interested in helping out with the chase that year. Since then I've been eagerly going back each year to provide weather updates for tour guests and help drive the thousands of miles we cover weekly to get to areas favorable for severe weather. I like chasing storms so much that I missed my college graduation from Mississippi State (don't worry, my meteorology degree is safe and secure on my wall at home) and had planned to miss my high school graduation if it had been scheduled a day later in conflict with my storm chasing trip. I've even had the chance to chase with Kevin Harned before since he chases with the same group from time to time. These yearly storm chases taught me much of what I know about severe weather and I use this knowledge daily to help forecast our weather around here in Kentuckiana. There are many reasons that people chase storms but my motives have always been education and the thrill of witnessing the beauty and power of these storms. Nobody wants to see a storm that harms life and property so we're always hopeful that the storms and tornadoes we see occur in remote, open areas. We're always practicing safety out there too by making sure we're far enough away from activity so that we can make a quick escape if necessary.

While I'm in the Plains next week you'll have a virtual front-row seat to our chase online and on-air. My most constant updates will be on Twitter, so be sure to click on the banner at the top of this post to follow me. I'll also have updates on Facebook and Instagram as well. You'll see daily posts here on the WAVE 3 Weather Blog from with forecasts, accounts of our chase day, and plenty of photos and video after we see storms. During our evening newscasts I'll be able to send back a live video feed at times when we have good enough cell service in these remote areas. Should we see any jaw-dropping storms or tornadoes you'll also see video from those experiences on-air. This is all in an effort the bring the chase home to you so that you can get a taste of what it's like to experience these storms firsthand.

A Peek at the Forecast

While we may set dates each year to chase storms, Mother Nature isn't always cooperative with that schedule. You may go out to the Plains for a week and see nothing but sunshine and blue skies (Kevin always jokes how this happens frequently on his storm chasing trips). Thankfully I don't think this upcoming week will be like that. For the past month now I've been looking at long-range data, and now, short range data to determing how the first few days of our chase will go. It appears that multiple shortwave disturbances aloft will be moving through during at least the first half of the week. This will provide the lift and southwesterly wind flow aloft (see green in western US, right) necessary to generate storms in places across the Plains.

On Sunday it looks like we'll likely drive a ways to position in western Nebraska or possibly even western South Dakota or Kansas depending on where the most favorable surface winds set up for maximum wind shear during the day. This will be dependent on how much an area of low pressure in eastern Colorado tightens up. This is a little tricky because there's a cold front that will be dropping through the region as well, so there may be a few areas of focus for storms. This, like just about every other severe weather setup, won't become crystal clear until the morning before it happens when we can see the actual surface observations and satellite imagery. The Storm Prediction Center has done a good job outlining the area of concern on Sunday with a 15% hatched Slight Risk area. Here's a snippet of their thoughts...

FARTHER SOUTH IN THE
WARM SECTOR...SWLY FLOW ALOFT WILL MAINTAIN PLUME OF STEEP LAPSE
RATES ALONG WRN EDGE OF RICHER LOW-LEVEL MOISTURE. THIS WILL
CONTRIBUTE TO A CORRIDOR OF MODERATE INSTABILITY OVER THE CNTRL AND
SRN HIGH PLAINS WITH 1500-2000 J/KG MLCAPE LIKELY AS THE BOUNDARY
LAYER WARMS DURING THE AFTERNOON. FORCING FOR ASCENT ASSOCIATED WITH
EJECTING IMPULSES AHEAD OF THE UPPER TROUGH...BOUNDARY LAYER
DESTABILIZATION AND CONVERGENCE ALONG THE LEE TROUGH SHOULD
EVENTUALLY RESULT IN THE DEVELOPMENT OF STORMS BY LATE AFTERNOON AS
THE CAP WEAKENS OVER THE CNTRL/SRN HIGH PLAINS. OTHER STORMS MAY
INTENSIFY ACROSS SD IN VICINITY OF THE FRONT. INCREASING HEIGHT
GRADIENT ASSOCIATED WITH THE PROGRESSIVE UPPER TROUGH WILL RESULT IN
VERTICAL SHEAR STRENGTHENING TO 40 KT...SUPPORTIVE OF ORGANIZED
STORMS INCLUDING SUPERCELLS. LARGE HAIL WILL BE THE INITIAL PRIMARY
THREAT...BUT AS THE LLJ STRENGTHENS...STORMS MAY EVOLVE INTO MCSS
WITH AN INCREASING THREAT FOR DAMAGING WIND DURING THE EVENING.

This bodes well for us because those supercells mentioned in the discussion above are the type of storm we're after since they tend to be the most severe and have a higher liklihood of generating tornadoes.

Monday's severe weather threat isn't quite a clear at this time since it will depend on the evolution of storms on Sunday and where surface features set up in the wake of that. Kansas could very well be the target for that day (see forecast EHI values to the right) but I'm not too impressed with the westerly to slightly northwesterly winds aloft we may have that day that some of the data is showing. Here's what the SPC says...

OTHER MORE ISOLATED ACTIVITY MIGHT DEVELOP ALONG THE SWRN EXTENT OF
THE FRONT ACROSS KS WHERE STRONGER SHEAR AND INSTABILITY WILL
EXIST...BUT COVERAGE MAY BE MORE LIMITED DUE TO STRONGER CAPPING AND
WEAKER FORCING.

This actually isn't as bad as it may sound because isolated storms are easier to chase and days with very high threats (Moderate and High risk days) can many times lead to fast-moving storms that are difficult and more dangerous to chase. Beyond Monday I do see other potential for severe weather but I won't comment on that now since we've obviously enough fish to fry with Sunday and Monday.

May 29, 2014

Radar is showcasing light rain showers passing through the area. This will be the norm as we head through the next few hours with a better shot at storms in the afternoon/evening. The longer we can hold onto this light rain...the better. This will limit the threat of stronger storms, and keep our temperatures a tad cooler...which will also limit bigger storms. Heat and sun will play against us today... so as long as we're locked in with clouds the threat is very low for severe storms.

TODAY

TIME IT OUT

SEVERE RISK

Widespread severe thunderstorms will NOT be an issue today. Like the last few days, a storm may power up just enough to briefly reach severe limits. Any severe thunderstorm warning that would be issued would likely be for wind. Much like the last few days, storms will increase with height, collapse, and strong winds will be pushed to the surface. In this scenario a random warning can't be ruled out today but we will not see widespread severe weather. In fact the longer we can hold onto cloudy skies with light rain the better. With that said...the rain/storms will be a bit more widespread today compared to earlier in the week. I know it's rough if you haven't recieved any rain this week as the storms have been very hit and miss. Some of us are tallying up a few inches and it's only Thursday, while others haven't seen a drop. No real pattern, rhyme or reason, to where these storms pop up today. I will say, with a cold front to our North, pushing South, and an area of low pressure to our South, pushing North, we are in the battle zone to see more storms today/tonight...so your chance of getting wet is a bit higher than the earlier part of the week. By tomorrow the front pushes South of us and takes the showers/storms with it. We'll end the week dry, especially the farther North you go, and start the weekend dry for many of us, too.

May 28, 2014

Another humid afternoon with scattered storms popping on the radar as I type this. Just like the past couple of days---a few may briefly turn severe when they collapse. That process can produce winds over 50 mph. Otherwise...expect mainly just tropical downpours and lots of lightning.

We do have some relief on the way later Thursday night into early Friday.

Currently we have high dewpoints over our region (blue/gray shading).

By early Friday morning---a cold front MOVING IN FROM the NE will actually drop those values down leading to a drier atmosphere. This should set the stage for a sunny (still hot) but less humid and storm-free setup Friday/Saturday and most of Sunday where the NE flow wins out. I will caution that this front is going to "wash out" over KY. So if it does not pass through your town---you may not see ANY dewpoint relief...and therefore a continued storm chance. Highest risk for such looks to be south/southwest of Louisville. So if you want a dry forecast..hope for that front to make it to you!!!

As mentioned, this front will wash out---so any relief we see looks to last about 48 hours before BAM!...the humidity is back in our area later Sunday/Monday. And so will be the storm chances.

LOOKING AHEAD...lots of talk now about how will this summer pan out.

Once again, I feel the drought will play the biggest role.

Here is the current drought index. Very intense to our west.

Comparing it to last year at this time---it was centered a bit more east over the Plains.

Given the drought setup--it appears the ridge will dominate over the western US and Plains. This will leave the eastern US at risk for several cold fronts through at least early summer.

Latest GFS shows such a pattern through mid June.

This doesn't mean we won't see 90 degree days..we will. But it looks overall to be an "average" summer temperature wise...but the humidity may be a bear. With several fronts--we could have lots of "green" on the ground with vegetation. While that keeps actual temps down some, it allows for excessive heat indicies at times.

Storm wise..it opens the door to several MCS (complexes of storms) patterns setting up from IL to VA. So we could have more severe weather over the summer than what we have faced during the spring.

Much of the day will be dry, but expect a storm or two... mainly during the afternoon and evening. It will be another warm and humid day with some sunshine with increasing clouds.

The storms today and tomorrow could help to reduce the pollen count, but so far it remains high for grass pollen and moderate for tree pollen.

The good news is that the storm chances go down during Waterfront Wednesday. You're still advised to bring a poncho or umbrella in case the showers pop up in the area.

The chance of storms will stick around in the forecast for tomorrow and to the south of Louisville for Friday. A slow moving front will linger in WAVE Country during the next few days which will keep that rain and storm chance in the forecast.

Even though we are not under a risk of severe storms today, we could see a few storms intensify with gusty winds and heavy downpours.

We are not expecting widespread severe storms for tomorrow either, but like today, some of the storms could be strong in this warm and humid environment. We will be monitoring the storms for strong winds, intense lightning, heavy downpours and possible hail.

May 27, 2014

The heat and humidity stays with us today and for most of the week. Save yourself the time and ditch the hairspray...the frizz factor will be out of control today. With dewpoint readings in the 60s and 70s it will feel very tropical outside. Current temps at 10:30am are below.

STORM THREAT

This Summer like atmosphere rolls on today with warmer than average temperatures and a shot at storms. Much like yesterday, the peak heating of the afternoon from lunch time to dinner time, will bring us the best chance to see a few storms, with scattered ones possible later tonight/overnight. Some models are hinting at a better storm chance this evening...so we're monitoring the trends on that. What develops today will have a direct impact on what holds together tonight...so we're in a wait and see mode at this point. The coverage will be a bit higher today/tonight compared to yesterday, but there will certainly be dry time too...especially the next few hours. Any storm that gets going will produce heavy rainfall and a lot of lightning. As far as severe weather, the threat stays low not only today but for the next several days. This set up just isn't favorable for severe storms. With that said, a random warning can't be ruled out today through Friday. Any warning that would be issued would be for wind. As these Summer like storms bubble up they'll quickly collapse and a strong gust of wind could be pushed at the surface...enough to briefly reach severe limits. This situation would be on an isolated basis at best.

PLAN YOUR DAY

RELIEF FROM THE HEAT

Despite the haze from the cirrus clouds, the Uv Index will still be high today at a 9. Grab the sunscreen before you head to the pool. Don't let the high clouds fool you...the sun will still sneak through and cause some pretty nasty sun burns.

May 26, 2014

Most of the afternoon storms have faded away this evening. However, I have noticed several left over boundaries lying all over the place. So it would not take much for one to react to the cool pockets of air aloft and develop at storm. Therefore, I am going to add a small overnight storm chance.

Latest RPM model has the risk.

The setup over the SE part of the county is one where high pressure is battling lows/fronts that surround it. This leads to daily showers/storms.

The winds aloft are fairly weak. Usually we see more yellows/reds when concerned about strong storms.

This means the storms the next few days will be updraft based. The winds aloft will not be there to keep the flow continuous. The end result? The storms will have a limited life-span. On the average of about 20-30 mins. However, when they mature---they can produce lots of lightning and heavy rain. Whey they start to collapse...the gust of wind risk is there. We call these "pulse-type" storms. Sometimes, the updrafts are so strong that severe winds are possible (58mph +). But at this time...I do not see that risk taking place.

Neverthess, be alert for afternoon storms through Friday.

There will be a backdoor cold front (moves in from the NE) that will arrive on Friday. That may be enough to lower humidity values and dry the air out for the weekend. So we are going with a dry forecast for Sat/Sun for now. But I caution, if this front doesn't push through---our stormy/humid pattern would continue. And/or if the front washes out too far---the southern flow will return.

Overall---this week will be more like July than late May. We will keep an eye on the storms the next few days. Some will have very intense lightning and may "sound severe" at times---but remember---for a warning-- you need the risk for 58 mph winds and/or 1" hailstones. NWS does not issue warnings for lightning.

As we remember those we've lost this Memorial Day, I wanted to give you a detailed look at the forecast. Whether you're visiting the cemetary, or hanging by the pool, this blog update has everything you need to know about the weather today, and the days ahead. I've made 9 different graphics today that will help you plan for the day. Lets dive in...

RADAR UPDATE...

Here's a snapshot of radar taken at 9:18 this morning. I've highlighted some areas we'll be watching throughout the afternoon. Notice a few storms developing in Tennessee...these will track North and East and if they grow could impact parts of our Southern viewing area later today. The northern top of this cluster is trying to squeeze out a few rain showers in Western KY. We'll watch for the development of these over the next few hours. Should they hold together and expand they've have an impact on more of our area throughout the day. My best advice since these storms today will be so hit and miss...is to download the Wave 3 Weather app. You can track the storms with us as they blossom this afternoon.

HIGH TODAY...

Average high temperatures this time of year are near 80, with overnight lows near 60. Both today and tonight temps will warm above average. Expect an afternoon high near 87 in Louisville on your Memorial Day. Dew point readings and humidity will start to ramp up quickly...this means a sticky, humid, day is on tap. With the rapidly warming temperatures and dewpoint, there is a chance for afternoon storms. It's important to point out before going into the forecast any further...today will NOT be a wash out. :) I just wanted to get that out there. Okay...lets keep moving...

HOW WE GET THERE...

We started the morning in the 50s and 60s with some fog around the area. As the fog continues to break down the sun will overtake the area and we'll start to see the temperatures warm quickly. At 10am temperatures will be near 76, 2pm at 84, 6pm 86, and 10pm around 78. Areas that stay rain free and mostly sunny today could easily touch 90...either way, it will definitely feel like the low 90s for some of us with the high humidity. Daytime heating will increase our chances for a few showers/storms. At this point I'm looking at lunch time to dinner time as an easy way to remember that you may need to dodge some random showers.

STORM CHANCE...

While the heaviest and most steady rain will stay West and South a few pop up showers/storms could develop based on the boundary slicing through the area. Much like a Summer set up, any rain we see today will be random in nature and bring some heavy downpours and lightning. Severe weather is not expected today. Today marks the start of a stormy pattern this week. I'd throw the umbrella in the car before you leave today and keep it with you through the weekend. Notice below on futurecast not much activity at 4:30pm today. Futurecast is also picking up on the idea that our shower chance today will be limited. If you get caught under one you may need to dart inside for a few minutes, but if you're lucky enough...it's possible you'll stay rain free all day.

Rain/storm percentage...

10am- 0%

12pm - 10%

2pm - 30%

4pm- 30%

6pm- 30%

8pm- 20%

10pm- 20%

12am- 10%

TONIGHT...

TOMORROW...

Tuesday brings a better chance for afternoon storms. The morning commute tomorrow should stay dry, but as lunchtime hits and temps warm expect a few more storms than what we'll see this afternoon. This threat will increase each day this week before HOPEFULLY we're able to squeeze out some dry time by the weekend.

WEDNESDAY...

Join me at 11am for Wave 3 News Midday with the latest live look at radar and new data rolling into the weather center. See ya then! - Lauren Jones

May 25, 2014

A shower can't be ruled out this morning in our western counties north of the Ohio River thanks to a weakening area of spotty showers moving in. With high pressure in place just to our northwest and slightly drier air here it'll be hard for these to stay together as they approach. Once these pass the rest of the morning and the early afternoon will remain dry.

By mid to late afternoon we can't rule out an isolated storm or two south of the Western Kentucky/Bluegrass Parkway. It'll be a battle between a boundary to our south, surface heating, and high pressure to the northeast in determining whether or not this will pan out. Just about all of the short-range data says Louisville will stay dry in all of this and even areas south of the parkways will only see the very small coverage of storms.

Memorial Day looks mostly dry as well, but the isolated storm chance in the afternoon will be extended to cover the entire area instead of just our southern counties. Briefly heavy rain and lightning will be possible in any of these storms that may form. While Monday had originally looked like our first 90 degree day of the year, weaker warm air advection from the south and the possibility of a little more cloud cover has made me pull back on those numbers a bit, now with a high of 87. Tuesday could make a run at 90 but with storms in the afternoon I'm not confident enough to put us past 89.

Those storms on Tuesday will be more widespread than Monday and this pattern will continue through Thursday as it looks now. With a cut-off low type disturbance moving in and washing out just to our west we'll have the chance to see enhanced thunderstorm activity during the afternoons on these days. Severe weather? I don't think so. Winds aloft will be very weak during all of this so short-lived pulse-type storms with heavy rain and lightning will be the primary mode of storms we see. By the weekend storm chances will decrease as we see this low wash out completely and a summer-like ridge pattern continue.

Hokey Weather Fact

Here's a Hokey one for you. What you see as a sunrise is actually an optical illusion! Since the atmosphere bends or refracts light as it passes through, you can see the sun before it actually peeks over the horizon. So, basically, what you see is a sunrise that's occurring just below the horizon. Pretty cool, eh? Be sure to click here for more Hokey Weather Facts.

This coming Saturday I'll be leaving on my annual week-long storm chasing trip to the Great Plains. This will be my 7th year forecasting and chasing storms with Storm Chasing Adventure Tours, which was an integral part of my weather education while in high school and college. While I'm out there next week you'll see daily blog posts about my chase here on the WAVE 3 Weather Blog as well as LIVE updates on my Twitter andFacebookaccounts. Be sure to follow me to keep up with the chase!